Question C asks how's to calculate the current over the led and 3k resistor? Can someone please help me understand how to do it?
20V supply and 2V across the LED leaves how much voltage across the 3K Ω resistor?
With that voltage, use ohms law to calculate the current through the 3K Ω resistor.
Calculate the current for a 470 Ω resistor at 2v.
There is more current flowing through the 3K Ω than the 470 Ω resistor.
Where would that excess I3K - I470Ω current go?